Hiya! Corpus Christi also falls on 23rd June this year, when the major towns have displays of "carpets of salt" through the streets. The area around San Gines church in Arrecife is the most well known.

The night of San Juan is when everyone is (legally) allowed to have bonfires, and at midnight it is down to the beach to walk backwards into the sea until the waves cover your head! That's the tradition here in Lanzarote anyway, though I know there are many variations throughout the islands and on the mainland.

I don't know of any special events organised I'm afraid.

HTH